Besides affecting the harshness of hits, what does the size of the bong have to do with how high you get? does water affect thc content? etc.
lolwut. Size has nothing to do with how high you get. To me, anything over 18 or 20 inches is just for show(as well as toking). THC and other cannabinoids are not very water soluble, so the amount of water you use only affects the drag.